We have this “show me” thing that will be our downfall. Something has to happen, preferably many times, before we believe it.

Like how many kids have to die before we get an understanding of gun violence? How many years were lost politicizing global warming?

We now face problems that make issues such as gun violence pall. Natural disasters forecasted to happen once every 100 years are compressing the time frame.

Last week’s astounding “show me” featured an asteroid exploding over an unlucky Russian city with the force of 30 Hiroshima atomic bombs (NASA estimate). The space agency says it was a once-in-1,200-year event.

Another space rock on the same day, Friday, missed us by 15 minutes — that’s an angle of one quarter of 1 degree — of our orbit. It was the “closest-ever predicted approach to Earth for an object this large,” says NASA. The rock was big enough to level New York City (800 square miles).

ASTEROID SIGHTINGS

The Associated Press by Sunday reported more asteroid sightings, one over Cuba, which exploded but caused no damage, and a flameout near San Francisco captured on cell-phone videos. Then on Monday, an asteroid broke up over the Atlantic off Miami.

This shows us the threat that scientists have been warning about for decades, to deaf ears. Nobody died, but our faith in our protectors did.

We’re naked, confronted with asteroid attacks. The issue has little research, almost no experts and zero political will (translation: no lobbyist cash).

DEFENSE

The neglect is so embarrassing that four astronauts are funding a spur to an anti-asteroid defense with their own money. That asteroid that brushed past us? It was discovered not by NASA or the Air Force but by an amateur with a telescope.

The closer the “show me,” the sharper the reaction. Alexei Pushkov, Russia’s chief of foreign affairs, wrote on Twitter Friday after touring the damage zone: “Instead of fighting on earth, people should be creating a joint system of asteroid defence.”

This close aide to President Vladimir Putin said the United States must join Russia and China in building the system. It was an easy pitch as the world devoured the YouTube videos of the meteorite explosion.

Will anything happen? No. There’s no cash.

We’re too busy spending billions on more important things, such as digging rock samples on Mars and indulging President Obama’s passion to beat the Chinese to the moon.

Our fear is that asteroid collisions remain beyond the intellect of our president and Congress. Our politicians will believe it only when — not if — America loses a city (reference 9/11). Our best asteroid defense so far is: How long will our luck hold?